SOLUTION: Tom Johnson and Melissa Acino started driving at the same time in different cars from Oklahoma City. They both traveled south on Route 35. When Melissa covered a distance of 207 &#

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Question 1128909: Tom Johnson and Melissa Acino started driving at the same time in different cars from Oklahoma City. They both traveled south on Route 35. When Melissa covered a distance of 207 ​miles, Tom had only covered a distance of 177 miles. If Melissa averaged 10 miles per hour faster than​ Tom, find the average speed of each car.
Found 2 solutions by greenestamps, josgarithmetic:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


Since the driving times are the same, the ratio of distances is the same as the ratio of speeds. Algebraically, if x is Tom's speed, then

207%2F177+=+%28x%2B10%29%2Fx

You could finish solving the problem from here using formal algebra....

207%28x%29+=+177%28x%2B10%29
...etc

But if you think of simplifying the fraction on the left before doing the algebra, the answer to the problem becomes clear:

207%2F177+=+69%2F59

69 is 10 more than 59....

ANSWER: The two speeds are 69mph and 59mph.

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Tom, speed r
Melissa, speed r+10

Same time, x.

system%28rx=177%2C%28r%2B10%29x=207%29

177%2Fr=207%2F%28r%2B10%29
-
207r=177%28r%2B10%29
207r=177r%2B1770
30r=1770
r=177%2F3
highlight%28r=59%29-------Tom's speed
highlight%2869%29--------Melissa's speed